Patterns of Inflammation in Experimental Autoimmune Uveitis and Their Correlation to Optical Coherence Tomography...

Experimental autoimmune uveitis (EAU) in rats is a pivotal model for understanding the immunological mechanisms of human uveitis and developing therapies. In humans, optical coherence tomography (OCT) allows for the in vivo detection of characteristic findings in active uveitis, as well as sequelae of inflammation. The objective of this study was to correlate OCT findings in patients with uveitis with retinal histologies from two rat models of EAU caused by T cells with different autoantigen specificities and well-known underlying immunological pathomechanisms. Patients with various noninfectious uveitis subtypes underwent imaging using an ultra-widefield swept source or conventional OCT. Histological cryosections from rat eyes with experimental autoimmune uveitis were stained for T cell and/or macrophage markers. Typical human OCT findings were reproduced in the experimental animal model. Hyperreflective signals observed on OCT corresponded to lymphocyte infiltration in histological sections. This infiltration was typically found as vasculitis in the perivascular regions and snowballs in the posterior hyaloid. There was lymphocyte and macrophage infiltration of the retina through the retinal vessels and the retinal pigment epithelium. Comparing in vivo OCT imaging of human uveitis with corresponding histologies from rat models improves our understanding of the type of inflammation, extent of tissue destruction, and immunopathogenesis.